VIALOG CORPORATION CALCULATION OF SHARES USED IN DETERMINING LOSS PER SHARE FOR THE THREE MONTHS ENDED MARCH 31, 1997 AND 1998 THREE MONTHS ENDED MARCH 31, ---------------------------- 1997 1998 -------------- ------------ BASIC LOSS PER SHARE - -------------------- Weighted average number of common shares outstanding 2,747,300 3,542,668 ============== ============ THREE MONTHS ENDED MARCH 31, ---------------------------- 1997 1998 -------------- ------------ DILUTED LOSS PER SHARE - ---------------------- Weighted average number of common shares outstanding 2,747,300 3,542,668 Common stock equivalents - - -------------- ------------ Total 2,747,300 3,542,668 ============== ============